这篇就三种拦截模式进行一下探索。
特性总结
| 类型 | 特点 | 其它 | |
| InterfaceInterceptor | Innstance | 仅单接口 | 类内部函数互相引用无法引起拦截行为 |
| TransparentProxyInterceptor | Instance | 多接口(接口之间能够切换) MarshalByRef 执行缓慢 接口类型（virtual, non-virtual, or interface） | 类内部函数互相引用能够引起拦截行为 |
| VirtualMethodInterceptor | Type | 多接口 不能用在已有对象上，接口函数必须为virtual | 类内部函数互相引用也能引起拦截行为 |
回顾一下类的声明。两个接口，一个实现。
fsharp实现接口函数的方法与csharp并不全然一致，会造成一些实现上的困扰，这在后面会提到。
type ITenantStore =
abstract member Msg : unit->unit
type TenantStore() as x=
//do printfn "new TenantStore %A" (x.GetHashCode())
interface ITenantStore with
member this.Msg() = printfn "Hello, it‘s TenantStore"
interface IDisposable with
member this.Dispose() = printfn "TenantStore hase been cleaned"
以下进行一些測试。
let showregistrations (container:UnityContainer) =
container.Registrations |> Seq.iter (fun i -> printfn "Regist Type:%A" i.RegisteredType)
using(new UnityContainer())(fun ctner->
ctner.AddNewExtension<Interception>() |> ignore
ctner.RegisterType<ITenantStore, TenantStore>(new Interceptor<TransparentProxyInterceptor>(),//兴许对此注入策略进行切换
new InterceptionBehavior<LogingInterceptionBehavior>()) |> ignore
showregistrations ctner
let t = ctner.Resolve<ITenantStore>()
t.Msg())
showregistrations 显示已注冊的类型。用来展示注冊内部的信息。另外，在交互式代码中使用using相较于use更为的合适，FSI声明的对象的生命周期是全局的，在做试验的时候无法控制container。重复清环境不太方便。
TransparentProxyInterceptor的结果
Regist Type:Microsoft.Practices.Unity.IUnityContainer Regist Type:Microsoft.Practices.Unity.InterceptionExtension.InjectionPolicy Regist Type:FSI_0002+ITenantStore From the logging interceptor: "Invoke method System.Type GetType():System.Object at 16:20:45" From the logging interceptor: "Method System.Type GetType():System.Object returned FSI_0002+TenantStore at 16:20:45" From the logging interceptor: "Invoke method Void Msg():FSI_0002+ITenantStore at 16:20:45" Hello, it‘s TenantStore From the logging interceptor: "Method Void Msg():FSI_0002+ITenantStore returned at 16:20:45" val it : unit = ()
InterfaceInterceptor的结果
Regist Type:Microsoft.Practices.Unity.IUnityContainer Regist Type:Microsoft.Practices.Unity.InterceptionExtension.InjectionPolicy Regist Type:FSI_0002+ITenantStore From the logging interceptor: "Invoke method Void Msg():FSI_0002+ITenantStore at 16:22:54" Hello, it‘s TenantStore From the logging interceptor: "Method Void Msg():FSI_0002+ITenantStore returned at 16:22:54" val it : unit = ()
尽管对象有两个接口，IDiposable接口和ITenantStore接口。拦截仍然成功了，所以支持多对象指的是接口之间的切换，并不是不支持实现多对象的类。
VirtualMethodInterceptor的结果
Regist Type:Microsoft.Practices.Unity.IUnityContainer Regist Type:Microsoft.Practices.Unity.InterceptionExtension.InjectionPolicy Regist Type:FSI_0002+ITenantStore Hello, it‘s TenantStore val it : unit = ()
拦截失败。 研究后发觉是由于Fsharp中并不直接支持Virtual方法，Fsharp实现接口成员，默觉得显示（explicit）实现，想要申明Virtual方法须要一些技巧。
可參考http://cs.hubfs.net/topic/None/73936
再定义一个測试类来试试VirtualMethodInterceptor。
type testClass() =
abstract member Test : unit -> unit
default x.Test() =
printfn "hello "
using(new UnityContainer())(fun ctner->
ctner.AddNewExtension<Interception>() |> ignore
ctner.RegisterType<testClass>(new Interceptor<VirtualMethodInterceptor>(),
new InterceptionBehavior<LogingInterceptionBehavior>()) |> ignore
showregistrations ctner
let t = ctner.Resolve<testClass>()
t.Test()
)
结果
Regist Type:Microsoft.Practices.Unity.IUnityContainer Regist Type:Microsoft.Practices.Unity.InterceptionExtension.InjectionPolicy Regist Type:FSI_0002+testClass From the logging interceptor: "Invoke method Void Test():FSI_0002+testClass at 9:30:27" hello From the logging interceptor: "Method Void Test():FSI_0002+testClass returned at 9:30:27" val it : unit = ()
拦截成功。
以下稍加改写原来的类定义。使接口都以virtural的形式暴露出来
type TenantStore() as x=
//do printfn "new TenantStore %A" (x.GetHashCode())
abstract Msg : unit -> unit
default x.Msg() =
printfn "Hello, it‘s TenantStore"
abstract Dispose : unit -> unit
default x.Dispose() =
printfn "TenantStore hase been cleaned"
interface ITenantStore with
member x.Msg() = x.Msg()
interface IDisposable with
member x.Dispose() = x.Dispose()
有些繁琐，接口实现的代码能够复用，不幸中的万幸。
以下的样例中我同一时候測试一下多接口之间转换的情况，看看VirtualMethodInterceptor是否也支持多接口。文档上没有明白表明。
測试代码
using(new UnityContainer())(fun ctner->
ctner.AddNewExtension<Interception>() |> ignore
ctner.RegisterType<ITenantStore, TenantStore>(new Interceptor<VirtualMethodInterceptor>(),
new InterceptionBehavior<LogingInterceptionBehavior>()) |> ignore
ctner.RegisterType<testClass>(new Interceptor<VirtualMethodInterceptor>(),
new InterceptionBehavior<LogingInterceptionBehavior>()) |> ignore
showregistrations ctner
let t = ctner.Resolve<ITenantStore>()
t.Msg()
let o = (box t) :?
> IDisposable
o.Dispose()
)
TransparentProxyInterceptor
成功 结果
Regist Type:Microsoft.Practices.Unity.IUnityContainer Regist Type:Microsoft.Practices.Unity.InterceptionExtension.InjectionPolicy Regist Type:FSI_0002+ITenantStore From the logging interceptor: "Invoke method System.Type GetType():System.Object at 9:38:47" From the logging interceptor: "Method System.Type GetType():System.Object returned FSI_0010+TenantStore at 9:38:47" From the logging interceptor: "Invoke method Void Msg():FSI_0002+ITenantStore at 9:38:47" Hello, it‘s TenantStore From the logging interceptor: "Method Void Msg():FSI_0002+ITenantStore returned at 9:38:47" From the logging interceptor: "Invoke method System.Type GetType():System.Object at 9:38:47" From the logging interceptor: "Method System.Type GetType():System.Object returned FSI_0010+TenantStore at 9:38:47" From the logging interceptor: "Invoke method Void Dispose():System.IDisposable at 9:38:47" TenantStore hase been cleaned From the logging interceptor: "Method Void Dispose():System.IDisposable returned at 9:38:47" val it : unit = ()
InterfaceInterceptor
失败 结果：
Regist Type:Microsoft.Practices.Unity.IUnityContainer Regist Type:Microsoft.Practices.Unity.InterceptionExtension.InjectionPolicy Regist Type:FSI_0002+ITenantStore From the logging interceptor: "Invoke method Void Msg():FSI_0002+ITenantStore at 9:39:44" Hello, it‘s TenantStore From the logging interceptor: "Method Void Msg():FSI_0002+ITenantStore returned at 9:39:44" System.InvalidCastException: 无法将类型为“DynamicModule.ns.Wrapped_ITenantStore_67632c824c8e42bbad5925d203ac819b”的对象强制转换为类型“System.IDisposable”。 在 [email protected](UnityContainer ctner) 位置 E:\WorkHell\fsharp-practise\EnterpriseLibraryUnity\Program.fs:行号 157 在 Microsoft.FSharp.Core.Operators.Using[T,TResult](T resource, FSharpFunc`2 action) 在 <StartupCode$FSI_0015>[email protected]() 已因出错而停止
VirtualMethodInterceptor
成功 结果
Regist Type:Microsoft.Practices.Unity.IUnityContainer Regist Type:Microsoft.Practices.Unity.InterceptionExtension.InjectionPolicy Regist Type:FSI_0002+ITenantStore Regist Type:FSI_0002+testClass From the logging interceptor: "Invoke method Void Msg():FSI_0017+TenantStore at 9:42:01" Hello, it‘s TenantStore From the logging interceptor: "Method Void Msg():FSI_0017+TenantStore returned at 9:42:01" From the logging interceptor: "Invoke method Void Dispose():FSI_0017+TenantStore at 9:42:01" TenantStore hase been cleaned From the logging interceptor: "Method Void Dispose():FSI_0017+TenantStore returned at 9:42:01" val it : unit = ()
通过结果能够看到TransparentProxyInterceptor在构建的过程中多了一些步骤。翻了一下帮助文档。说这个代理是使用 TransparentProxy/RealProxy infrastructure生成的。因而速度最慢。
而另两个则是通过动态代码生成的（这是什么？反射？）。
这里能够有个小的结论了，InterfaceInterceptor最小巧有用，其它两个或多或少在使用上都要留意一下各自的特性。
再看看可替换性。
(box t) :?> TenantStore
结果
TransparentInterceptor 失败
VirtualMethodInterceptor 成功
InterfaceInterceptor 失败 和料想的一致
以上
时间： 2024-11-05 19:26:30